1. Field of the Invention
The present invention relates to a progressive modular distributor for volumetric division, between a plurality of outlets, of a lubricant fluid.
2. Description of the Related Art
The lubricant fluid may be oil or grease supplied under pressure to the distributor. Said distributors are currently marketed by the applicant with the trade name SXO and are formed of a plurality of progressive distributor elements sandwiched between two bases.
The system uses a single input line and distributes incoming lubricant to a series of outlets. The lubricant is sent to the outlets sequentially. The distributor of lubricant fluid to the various outlets is volumetric and therefore always perfectly controllable.
The system provides a plurality of modular elements (or modules), each provided with two lubricant outlets. Depending on the number of outlet lines necessary, more modules may be added, which must simply be positioned between the two sandwiched bases.
Each module provides a series of passages which send the lubricant fluid to the modules upstream and guarantee their functioning.
In particular, each modular element provides a mobile cylinder inside it which has two operating positions. When the cylinder passes from one operating position to the other, it supplies to the device outlets a pre-set quantity of lubricant.
The modules have internal passages and the cylinders with a shape of a known type, such that the cylinders of each module move in sequence first towards the first operating position, then towards the second, following a pre-set cycle.
Therefore, with a single line to distribute the lubricant, total control of the system is allowed by means of a single sensor mounted on any one of the pistons (distributor elements).
As the movement of one piston is the essential condition for movement of the following position, all the progressive distributors of a system are connected in series and if a piston of any one of the distributors blocks off, even if belonging to another pack, the entire system therefore automatically blocks off.
This feature is very important for control of a centralized system: it is, in fact, sufficient to control with a micro-switch or with a magnetic reader or, better, with an inductive sensor, any outlet of a distributor to control the entire system.
As known, in order to allow ‘modular’ construction of the passages of fluid between the different modules, there are holes on the surfaces of all the modules. When two surfaces of two successive modules are rested, the various holes are aligned and, by means of appropriate O-rings, sealed passages are created between two successive modules.
The pressures in play in these devices are extremely high, so the surfaces of two adjacent modules must be perfectly resting to avoid leakage.
When standard tie rods are used, the modules and the bases must be positioned on a perfectly horizontal surface and the tie rods tight as a consequence.
However, this technique is laborious and often not possible ‘in the field’, for example during plant maintenance.
Therefore, in order to keep the modules aligned with each other, it has been chosen to make calibrated holes in each module, inside which the tie rods, also calibrated, pass, to maintain alignment.
Use of tie rods for centring the various modules is very impractical. It is, in fact, necessary to manufacture ad hoc tie rods, with a perfectly calibrated diameter and therefore extremely expensive.
Further, during assembly, it is extremely difficult to insert the tie rod in the holes, in view of the minimum tolerances necessary to ensure the centering function of the coupling.
A cost problem therefore exists in the prior art, relating to manufacturing calibrated holes on the modules, purchase of special tie rods (the length of which must also be adapted every time to the number of modules) and the assembly times, which are lengthy and must be performed by skilled operators.
There is also a problem strictly linked with maintenance. Each time a module must be replaced, it is necessary to remove the tie rods and dismantle the entire distributor.